This invention relates to a resistance unit for an exercise device such as a bicycle trainer or the like.
Exercise devices commonly utilize resistance units for providing resistance to a person performing an exercise. Several types of resistance mechanisms have been developed for use in resistance units, and include magnetic, fluidic and electronics resistance mechanisms. Typically, the resistance mechanism is located within a housing and is interconnected with an input member which is subjected to a force by a user during exercise, with the input member functioning to impart rotation to the resistance mechanism within the housing.
In some types of exercise devices, a significant amount of heat can buildup in the housing and have an adverse impact on overall performance of the resistance mechanism. For example, in a fluid-type resistance mechanism, build up of heat within the housing can effect the viscosity of the fluid and thereby the resistance imparted by the resistance mechanism. In addition, heat buildup can have a negative impact on the life of the seal which functions to maintain the fluid within the housing. Buildup of heat can also adversely effect the overall performance and life of other types of resistance mechanisms, such as magnetic or electronic resistance mechanisms.
Many types of resistance units, including those incorporated in bicycle trainers, utilize a shaft which is rotatable in response to an external force exerted by a person during exercise. The shaft rotates in response to the external force, and rotation of the shaft is resisted by the resistance mechanism. In a bicycle trainer, a roller is commonly fixed to the shaft and engaged with the rear wheel of the bicycle for driving the roller in response to rotation of the bicycle wheel. In the past, the shaft has been supported in a manner tending to allow the shaft to wobble or to slide back and forth along its longitudinal axis.
It is an object of the present invention to provide a resistance unit which substantially eliminates problems associated with heat buildup in the resistance mechanism. Another object of the invention is to provide such a resistance unit which takes advantage of existing structure in order to prevent buildup of heat in the resistance mechanism. Yet another object of the invention is to provide such a resistance unit which utilizes energy imparted by the exerciser to cool the housing of the resistance unit. A still further object of the invention is to provide a cooling arrangement which is suitable for use in connection with various types of resistance mechanisms, such as fluidic, magnetic or electronic resistance units. Yet another object of the invention is to provide such a resistance unit which is relatively simple in its components and construction, yet which effectively prevents buildup of heat in the resistance mechanism. Yet another object of the invention is to provide such a resistance unit which ensures consistent positioning of the shaft relative to the housing and to the shaft supporting components of the resistance unit.
In accordance with one aspect of the invention, a resistance unit for an exercise device includes a housing defining an interior, and a shaft having a first portion located within the interior of the housing and a second portion located exteriorly of the housing. The shaft is interconnected in the exercise device so as to rotate in response to application of an external force by a person performing an exercise. A resistance mechanism is interconnected with the first portion of the shaft and is located within the interior of the housing for providing resistance to the person""s movements. An inertial member is interconnected with the second portion of the shaft and is rotatable therewith. The inertial member includes a blade arrangement which is operable to direct ambient air toward the housing upon rotation of the inertial member by rotation of the shaft. Such movement of air toward the housing is operable to prevent buildup of heat within the housing caused by operation of the resistance mechanism. In one embodiment, an input member is engaged with the second portion of the shaft. The input member may be in the form of a roller member fixed to the shaft and located between the housing and the inertial member. The resistance unit may be incorporated in a bicycle trainer, and the roller member may be engageable with a wheel of a bicycle for imparting rotation to the shaft in response to rotation of the bicycle wheel.
The inertial member is preferably in the form of a combination flywheel and fan member mounted to the second portion of the shaft and rotatable with the shaft. The combination flywheel and fan member may be constructed so as to include a hub section secured to the second portion of the shaft and an annular outer ring section located outwardly of the hub section. The blade arrangement is located between the hub section and the annular outer ring section. The blade arrangement may be in the form of a series of blades extending between and interconnecting the hub section and the outer ring section, with the blades being spaced apart from each other so as to define an open area between adjacent blades.
The shaft extends along a longitudinal axis, and the combination flywheel and fan member is spaced from the housing. The blade arrangement is constructed and arranged so as to move air laterally in a direction parallel to the longitudinal axis of the shaft toward the housing, upon rotation of the shaft and the combination flywheel and fan member. In a construction wherein an input member is located between the housing and the combination flywheel and fan member, the blade arrangement is operable to move air past the input member toward the housing.
In accordance with another aspect of the invention, an improvement in an exercise device incorporates a rotatable fan arrangement interconnected with the resistance mechanism and located exteriorly of the housing within which the resistance mechanism is contained. The fan arrangement is constructed and arranged so as to rotate in response to movement of a person performing an exercise, and to direct air toward the housing of the resistance mechanism. Further details of this aspect of the invention are as set forth above.
Another aspect of the invention contemplates a bicycle trainer having a frame adapted to support a rear wheel of a bicycle, in combination with a resistance unit mounted to the frame. The resistance unit includes a housing, a rotatable input member engageable with the rear wheel of the bicycle, and a resistance mechanism interconnected with the rotatable input member and located within the housing. An inertial member is interconnected with the rotatable input member and located exteriorly of the housing, and the inertial member includes blade structure which is operable upon rotation of the inertial member to direct air toward the housing. Again, additional details of this aspect of the invention are as set forth above.
Yet another aspect of the invention involves an improved arrangement for mounting a shaft to a support structure in a resistance unit. The shaft is interconnected with an input member, such as a roller, and the support structure includes a pair of spaced support areas. A bearing member is engaged with each support area for rotatably mounting the shaft to the support structure. The resistance unit further includes a housing defining an interior within which a resistance mechanism is located. The shaft extends into the interior of the housing for connection to the resistance mechanism, through an opening in the housing. A third bearing member is engaged with the housing at a location spaced from and adjacent one of the bearing members engaged with one of the support areas of the support structure. Engagement structure is interposed between the housing and the support structure for locating the housing relative to the support structure. The third bearing member is operable to fix the position of the shaft relative to the housing, to prevent shaft wobble. In a fluid-type resistance mechanism, the third bearing member is located adjacent a seal engaged with the housing and with the shaft, and the third bearing member functions to ensure alignment of the shaft with the seal.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.